The current study addressed two questions pertaining to lobular carcinoma in situ (LCIS) of the breast. First, does the risk of a subsequent carcinoma decrease over time after an LCIS biopsy and second, what is the clinical significance of E-cadherin-reactive LCIS?
Eighty-two consecutive patients with a biopsy containing LCIS only, no prior history of breast carcinoma, and follow-up information available for the period 1955–1976 were reviewed. No patients underwent a mastectomy for LCIS. Four hundred eighty-six sections were stained with E-cadherin. E-cadherin reactivity was correlated with clinicopathologic features of the LCIS and subsequent tumors. The mean number of blocks stained per case was 5.9. The mean follow-up period was 21.6 years.
Sixteen patients (19.5%) developed 21 subsequent invasive carcinomas (9 ipsilateral, 2 contralateral, and 5 bilateral carcinomas). The 10-year and 20-year actuarial rates of developing subsequent carcinoma were 7.8% and 15.4%, respectively. Six of the 21 carcinomas (29%) developed after 20 years. Nine LCIS cases (10.9%) had focal E-cadherin reactivity. When compared with patients with nonreactive LCIS, patients with E-cadherin-reactive LCIS more frequently developed a subsequent ipsilateral carcinoma that had a ductal component (55.5% vs. 12.3%; P < 0.01). The subsequent carcinomas also developed after significantly shorter time periods (mean of 7.6 years vs. 19.6 years; P < 0.01).
LCIS appears to confer a persistent, increased risk of subsequent breast carcinoma that does not appear to decrease over time. E-cadherin reactivity appears to identify a subset of LCIS patients with risk factors for subsequent carcinoma similar to those of patients with low-grade intraductal carcinoma. Cancer 2001;92:738–47. © 2001 American Cancer Society.